1. Field of the Invention
The present invention relates to an apparatus for holding a dam unit which can be raised and lowered. The dam unit can be, in particular a weir or a turbine generator module having a number of turbine generator units. These turbine generator units can be arranged alongside one another and/or one above the other. Such dam units are arranged between two fixed-position dam structures, in particular piers, of a dam installation for a liquid medium. The invention may have particular application in a weir installation on a waterway. The invention also provides for a method for holding and raising or lowering such a dam unit, and to an associated dam installation.
2. Discussion of Background Information
Dam installations in waterways generally have at least two fixed-position dam structures, such as piers, between which a dam unit is arranged. These dam units can be a gate, a weir, a flap, a turbine generator module having a number of turbine generator units which are arranged alongside one another and/or one above the other and are connected to one another. Such dam units make it possible to carry out the specific function of the dam installation, for example as a weir installation, as a level-controlled dam for maintaining a specific water level for ship movements, or as an irrigation dam etc. These dam units can generally be raised and lowered in order to make it possible to clear the waterway, particularly in emergency situations. This can occur, for example, in the event of a flood. For this purpose, such dam units are guided, via suitable guide devices (such as guide grooves in the piers and guide rollers on the dam unit) in the dam structures of the dam installation. The dam units can thus be raised and lowered via lifting devices which are provided on the dam installation. Cranes are typically used as the lifting devices.
Normally, a dam installation of the type just described comprises a number of dam structures which are arranged alongside one another, and a corresponding number of dam units. However, only one crane is generally utilized, for cost reasons. It is thus necessary to use apparatuses which allow the dam units to be held in a raised position without the aid of the crane.
In known installations of this type, bars are placed transversely underneath portions of the dam units. The bars are installed via the guide grooves in the pier, and the guide rollers of the dam units are allowed to rest on the bars. In this way, the dam units are held in a raised position. Such an arrangement of the bars has the disadvantage in that the bars are mainly subject to bending loads and need to be of an appropriately large size in order to support the heavy weights or loads of such dam units. Another disadvantage is that forces are introduced into the dam structure very close to the edge. This is because the guide devices are, of course, arranged at the edge of the dam structure. As a result, only small cross-sectional areas are available for withstanding the load. As such, the loads which can be transmitted using the bars are, in consequence, at best small.